Leather sanding machine



Nov, 6, 1951 H. THEDE 2,573,936

LEATHER SANDING MACHINE Filed Fb. 2, 1949 Afro/wrm m Patented Nov. 6, 1951 Harold Thede, Sheboygan,

Wis., assignor to Armour and Company, Chicago, Ill., a corporationvof Illinois Application February 2, 1949, Serial No. 74,194

2 Claims.

l This invention relates to a leather treating machine and method. The invention is particularly useful in the shaving and bufflng of leather -through a rotary cylinder equipped with an abra sive sheet. .Y

. In the present practice for shaving and bufng leather, an abrasive sheet is wound about a cylyinder andthe cylinder is brought into contact with leather for finishing the surface, small air jets being directed against the abrasive sheet to yremove leather fragments collected thereon and fpaper for the removal of leather fragments, etc.,

whereby the life of the paper is increased and more effective abrasion of the leather surface is brought about. Yet another object'is to provide a machine and method whereby a flat curtain or 'sheet of air is directed against the paper on the cylinder to eliminate channeling while at the 'same time effectively clearing the surface of the paper vof fragments. A still further object is to provide an air-delivering conduit with means 'whereby a flat and substantially continuous air sheet or curtain is impinged upon a rotating cylinder bearing an adhesive sheet for increasing the effectiveness of the abrasive sheet while greatly increasing its effective life. Other specific objects and advantages will appear as the specication proceeds.

'Ihe invention is shown in an illustrated embodiment, by the accompanying drawing, in which- Figure l is a broken perspective View of a machine embodying my invention; Fig. 2, a schematic view in side elevation showing the arrangement of the main operating parts; Fig. 3, a broken View in side elevation of the air pipe or conduit equipped with slotted nozzles; Fig. 4, a plan view of the structure shown in Fig. 3, with a portion of the pipe shown in horizontal section; and Fig. 5, a plan view of the air jet tube or pipe and its actuating arm.

The apparatus for abrading leather in which an abrasive sheet-covered cylinder is employed is Well known in the art and a detailed description is believed unnecessary. In the illustration given,

I'Il designates a frame inwhich a trunnionequipped cylinder II ismounted for rotation. The shaft of the cylinder is shown equipped with a pulley wheel I2 driven by a belt I3. Itwill be understood that any means for rotating the cylinder may be employed. The frame I0 also provides a platform I4 for receiving the leather'piece I5 to be treated. Supported in the frame is a steel roller I6, and therebelow a resilient roller Il formed of rubber or other suitable material.

At the rear of the machine, the leather piece may be fed out of the machine above the cross girt IIll or, if desired, below the cross girt.

At the rear of the machine is an air jet tube I8 mounted for reciprocation in guides I9, and the tube is equipped with an actuating arm 20.

The actuating arm 20 is provided with an inturned end portion received within a spiral slot 2I of a rotatably-mounted cam member 22. The cam member is equipped with a shaft carrying a pulley 23 driven by a belt 24 also engaging a pulley carried upon the shaft of cylinder I I.

The tube or pipe I8 is provided throughout its length with spaced threadedopenings into which are secured threaded nozzles 25. The nozzles are provided with an air passage 26, and the outer end of the nozzle is provided with'a narrow transverse slot 2l, as shown more clearly in Figs. 3

' resilient roller I1.

and l.' The nozzles are arranged so that the transverse slots 2l are aligned, as indicated in Fig. 3, and each of the nozzles delivers a flat fanshaped stream, as indicated best in Figs. 2 and 5. The fan-shaped flat streams preferably overlap as they strike the abrasive-covered sheet of the cylinder and form a substantially continuous flat curtain or sheet of air extending across the face of the abrasive sheet 28.

The abrasive sheet may be of any type or structure. Ordinarily, the abrasive sheet consists of paper having abrasive material bonded thereto and it is wound around the cylinder and locked thereto by movable clamps (not shown) Compressed air or other gas may be supplied to the reciprocating tube I8 by any suitable means. In the specific illustration given, a flexible air tube 29 is connected to the tube I8 at 30 and the tube 29 leads to a compressed air reservoir or to any other source.

piece I5 is fed forwardly over the platform I4 and between the steel roller I6 and the rubber or a The more rapidly driven cylinder II carrying a sheet 28 of abrasive, shaves -buffe'd llesides using only 58 sheets.

is rendered elfective for engagement with a new.'

surface of the leather piece.

While employing no more air than has heretofore been employed in the: air-jetpipe andi other conditions remaining thesame, I; nd thatthe flat sheet or curtain of air produced by the combined slotted nozzles eliminateschanneling .while at the Same time greatly increasing the life of the abrasive sheet. At the same time, theabrasive sheet, by virtue of the uniform removal 0f leather fragments `therefrom',"is-much more effective in the abradingl operation. Y

For example, ina they use ofstandardapparatus, it iscommonv toget sand paper scratches or lines onthe leather, and if-'these are excessive innumber. or too deep, it is necessary to 1re-buff vthe leather.

Withthe new structure, there are fewer ofV 'such sand paperscratches or lines and rebuing is notnecessary. i

'In tests madewith-l theprior` type of machine inwhich ordinary air jets-were'discharged against the sand paper,` and. withY `the new machine in Which slotted nozzlesfwere employeifit was found that with the standard-.machine employing the perforated pipe, -83-sand Ypaper sheets were employedfor buiing 10,277 vleather sides, while with the .new machine employing the fanv jet or slotted nozzle vstructure 11,664 sides were buffed while using only 58 sheets. the new machine. almost doubledthe life of the abrasive sheets.

In another test the old machine-with the perforated. pipe buied 11,664 sides using 94 abrasive sheets while the vnew machine with the fan jet Over. .a series of tests, it wasfound that the oldmachine withvthe perforated pipe buied 123 sidesiper sheet while-*the new machine employing the fan jet air pipe buffed 20.1, sides` per sheet. The savings in onesmallplant using seven machines was $259.55 per` week,v or $12,978.00 per year.

Why the above `surprising result is. achieved, I amnot .fully able to explain. Y It .may be that the It will thus be seen that Y jets heretofore employed produced 'eddying, causing the fragments to be rearranged upon the abrasive sheet surface with channel effects, while the fiat stream, in addition to removing the fragments, serves as a barrier to prevent return of the fragments to portions of the surface. In any event, the use of the same amount of compressed air in the 'atxsheet orl curtain-like arrangement described not only eliminates Vchanneling and presents a uniformly cleaned abrasive sheet for A,engagement with new leather surfaces, but also `the .eiective Ylife of the abrasive sheet is almost doubled.

While: in. the. .orfegoing specification, YI have setfrth a singleembodiment in considerable detail-f'orthe purpose of illustrating the invention,

it.willbe.understood that such details of structure maybe varied widely by those skilled in the art without-departing from the spirit of my invention.

I claim: 1. In au leather-treating vmachine Vhaving a driven `cylinderi equipped withY 4-V`an abrasive'. -sheet and'Y a Yresilient rolls` for urging a leather strip against said abrasive sheet, an" airY jet. .pipe mounted for reciprocation in front of .said-:cylinder and provided. with spaced openings, rmeans for reciprocating; said pipe,and slotted means :associa-ted withssaid pipeaopening'for directingLhorifzontally-alignedk fan-shaped` streamsl of. air toward the abrasivevsheet osaid'cylinder,

k2V. Ina process .for abrading'leatherin which an abrasive sheet-covered cylinder rotated against the leather to; be treated, the stepsoffimpingng against the abrasive-:sheet surface, on fthe cylinder a flat substantiallycontinuous.curtainof air` extending longitudinal-ly of'. the fcylinldenfand reciprocating'y saidz curtainalongitudinally of; vthe cylinder.

HAROLD 'TI-IEDE.

REFERENCES CITED The following `references are of record inthe file of thisY patent:

UNITED 'STATES PATENTS Number NameV Date;

382,041 -Iea-v-y May l, 1188-8 1,218,339 Thurstonu MaryG, 1917 1,975,349 CuI'ti-n, V Oct'.'21934 2,087,238' VvBrostrom July/20, 1937 2,262,801 Hadavvay-.` Nov. :18, 1941 2,482,775 `Hollick Sept. 27,1949 2,482,781 

